Re: [Qemu-block] Migration sometimes fails with IDE and Qemu 2.2.1

[Peter Lieven]

Am 06.04.2015 um 20:50 schrieb John Snow:
>
>
> On 04/06/2015 02:47 PM, Peter Lieven wrote:
>> Hi all,
>>
>> is there a known issue in Qemu 2.2.1 where IDE stalls sometimes after a 
>> migration with Qemu 2.2.1?
>> The migration succeeds, but it seems that the complete I/O is hanging. This 
>> happens only sometimes
>> and only with extreme old Linux Guests (SLES 10 with Kernel 2.6.16) thus the 
>> IDE controller as
>> storage controller for the system disk.
>>
>> Maybe this sounds familiar to someone.
>>
>> Thank you,
>> Peter
>>
>
> It's news to me.

Okay, I was hoping that I just missed a patch or someone forgot to CC 
qemu-stable... :-)

>
> Is this a regression?

I can't say we see those vServers hang sometime after migration since we 
changed the hypervisor from qemu-kvm-1.2.0 to qemu-2.2.0.


> Any particular workload or reproducer?

Workload is almost zero. I try to figure out if there is a way to trigger it.

Maybe playing a role: Machine type is -M pc1.2 and we set -kvmclock as
CPU flag since kvmclock seemed to be quite buggy in 2.6.16...

Exact cmdline is:
/usr/bin/qemu-2.2.1  -enable-kvm  -M pc-1.2  -nodefaults -netdev 
type=tap,id=guest2,script=no,downscript=no,ifname=tap2  -device 
e1000,netdev=guest2,mac=52:54:00:ff:00:65 -drive 
format=raw,file=iscsi://172.21.200.53/iqn.2001-05.com.equallogic:4-52aed6-88a7e99a4-d9e00040fdc509a3-XXX-hd0/0,if=ide,cache=writeback,aio=native
  -serial null  -parallel null  -m 1024 -smp 2,sockets=1,cores=2,threads=1  
-monitor tcp:0:4003,server,nowait -vnc :3 -qmp tcp:0:3003,server,nowait -name 
'XXX' -boot order=c,once=dc,menu=off  -drive 
index=2,media=cdrom,if=ide,cache=unsafe,aio=native,readonly=on  -k de  
-incoming tcp:0:5003  -pidfile /var/run/qemu/vm-146.pid  -mem-path /hugepages  
-mem-prealloc  -rtc base=utc -usb -usbdevice tablet -no-hpet -vga cirrus  -cpu 
qemu64,-kvmclock

Exact kernel is:
2.6.16.46-0.12-smp (i think this is SLES10 or sth.)

The machine does not hang. It seems just I/O is hanging. So you can type at the 
console or ping the system, but no longer login.

Thank you,
Peter